RRS James Cook Cruise 27, 05 AUG-03 SEP 2008. Investigating landslide and gravity flow geohazards along the northeast Atlantic continental margin

The primary aim of JC027 was to collect sediment cores from a series of deep-water basins along the northeast Atlantic continental margin, in order to determine the character, frequency and potential geohazard of landslides and gravity flows in the region. Target areas included the submarine slopes north of the Canary Islands, the Agadir Basin, the Seine, Horseshoe, Tagus, Iberia and Biscay Abyssal Plains, and a series of feeder canyons and channels. In addition, Autosub6000 was deployed on its first scientific missions in order to investigate the erosive power of large-scale gravity flows in canyon mouth environments. Despite a late change to the schedule, JC027 proved to be a highly successful cruise. A total of 63 stations were visited, with deployments including five Autosub6000 dives, five megacores and 55 piston cores. There was very little weather or technical downtime, which ensured that all of the main objectives were achieved. Cruise highlights included 1) recovery of sufficient core data to allow development of a detailed chrono-stratigraphy for all of the major basins between the Canary Islands and the UK, aiding identification of areas where landslides and gravity flows may pose a potential geohazard to European coastlines, 2) collection of a series of spectacular high-resolution multibeam bathymetry images of giant erosional scours (using Autosub6000), which are providing new insights into scour formation and the flows that formed them, 3) new data illustrating the complexity of sedimentary processes and deposits in deep-water environments, including flow transformations, and 4) new discoveries about seabird distribution and behaviour in deep-water regions of the northeast Atlantic.